The overall objectives of the program are to develop and apply methods based on radioactive tracers that are useful in medical diagnosis and in studies of human biochemistry and physiology. We will continue the development of new radiopharmaceuticals and instrumentation for visualizing and quantifying the distribution of radioisotopes in man, and for studying the time-course of accumulation and disappearance of radioactive tracers from local sites within the human body. Our program includes the design, construction and application of data storage, processing and display systems. It also includes a quantitative study of the various parameters of isotope scanning. We propose to continue to investigate how radioactive tracers can be used to measure safely in man previously unmeasurable physiological and biochemical processes. Techniques developed and knowledge obtained should be of value in medical diagnosis, objective evaluation of treatment, and improved understanding of diseases processes. Such research is essential to the continued development of the new field of nuclear medicine, one that has grown rapidly over the past decade, due in part to the success of the work supported by this program-project grant. Areas of investigation are broad and include the brain and cerebrospinal fluid, the blood-forming organs, the heart, lungs, gastrointestinal tract, kidneys and musculoskeletal system. We will continue development of systems for automated detection of bacterial growth, for continuous monitoring of the effectiveness of renal dialysis systems, and for monitoring of physiological processes, such as cardiac output.